thats because of the limits of RA, and that building size and unit sprites are limited to the RA unit/building they're supposed to be
1. The rocket launcher is not considered as a turret, so it won't rotate
2. Thats because it is coded as an RA unit and is not specialised to have the seperate rocket graphics
3&4. The maximum graphics size of these buildings is too small for the Tiberian Dawn equivalent so they had to be shortened down to fit, its been done on a few units too (like the harvesters)